Dataset before being written to:
 [ 99 99 99 99 99 99 99 ]
 [ 99 99 99 99 99 99 99 ]
 [ 99 99 99 99 99 99 99 ]
 [ 99 99 99 99 99 99 99 ]
Dataset after being written to:
 [  0 -1 -2 -3 -4 -5 -6 ]
 [  0  0  0  0  0  0  0 ]
 [  0  1  2  3  4  5  6 ]
 [  0  2  4  6  8 10 12 ]
Dataset after extension:
 [  0 -1 -2 -3 -4 -5 -6 99 99 99 ]
 [  0  0  0  0  0  0  0 99 99 99 ]
 [  0  1  2  3  4  5  6 99 99 99 ]
 [  0  2  4  6  8 10 12 99 99 99 ]
 [ 99 99 99 99 99 99 99 99 99 99 ]
 [ 99 99 99 99 99 99 99 99 99 99 ]
